Whole genome-based polyphasic characterization of novel actinobacteria isolated from Antarctica Horseshoe island and investigation of their biotechnological potential

The poles are one of the coldest and most mysterious regions of our planet. The poles contribute to regional microdiversity thanks to the extreme conditions and isolation they provide. Such biodiversity corresponds to the potential production of new metabolites, owing to unique and versatile metabolic features. In this context, it is of great importance to isolate and analyze actinobacteria with high biotechnological potential and value, such as antibiotic production, from polar extreme conditions. In this study that analyses actinobacterial diversity of the Antarctic Horseshoe Island for the first time, it was aimed to isolate actinobacteria from soil, sediment and water samples from the island, to identify new species by molecular analysis and to characterize them with a polyphasic approach. In addition, it is aimed to reveal the biotechnological potentials of new species by using bioinformatic tools and to bring them to the literature. In this study, actinobacteria were isolated from samples taken from 23 different localities of Horseshoe Island using 18 selective media. In this context, 389 isolates were purified and their morphological characteristics were examined, and 68 psychrophilic and psychrotolerant isolates were identified at the genus level by 16S rRNA gene sequence analysis. As a result of 16S rRNA gene sequence analysis, it was determined that there are 20 different genera and 11 of them belong to members of actinobacteria. Among these, 31 isolates were evaluated to have high potential to become new species, genotypic characterization of all of these isolates and chemotaxonomic and phenotypic characterizations of some of them were performed. As a result of the thesis study, it was observed that all isolates, except Micrococcus sp. H39-S4, had the potential to become new species, and are very rich in terms of biosynthetic gene clusters and metabolic potentials. At the end of this thesis, new strains from the strains whose polyphasic analysis has been completed will be brought to the literature.